With the collapse of the USSR in 1991, the Soviet armed forces were largely disbanded and some of their personnel were distributed among the newly independent republics. With few options, the author joined the Redut organisation which consisted of Russian mercenaries operating abroad. In the years that followed, the rise of Valdimir Putin after he became President led to a strong nationalist sentiment developing in the Kremlin. Two former Soviet republics, initially Chechnya and then Georgia, were the first to be subjected to a growing Russian aggression. Special sabotage teams and assault battalions were created, each based on the Redut group, and the author, who had acquired the call sign ‘Viper’, soon found himself once again in Russian pay. This time, though, he was leading a special forces group in operations in Donetsk in the eastern part of Ukraine. In the autumn of 2021, ‘Viper’ was appointed to command the intelligence unit of the Redut group as part of the GRU. He was given three secret agents. These were Ukrainian special forces officers who had defected to Russia. They were handed a secret mission – to attack the headquarters in Kyiv of the Ukrainian Counter-Intelligence and Security Service, the SBU, and destroy all its files ahead of Putin’s full-scale invasion of the country. Putin's ‘Viper’ Detachment is the first full account by ‘Viper’ himself of this secret operation and how his unit had to fight its way out of Ukraine after the attempt on the SBU headquarters failed. A tense, full-throttle, struggle ensued, which ultimately led the battle-hardened author refusing to fight or kill anymore. He pulled his platoon out of the Ukraine and into Belarus, pursued by Putin’s counter-intelligence officers. Eventually, ‘Viper’ managed to escape Russia and went to the International Criminal Court in Hague to testify about war crimes committed by Putin's government. This is the first time the world will read about this secret operation recounted by the man who led it. In this book, ‘Viper’ reveals true nature of the hidden war in Ukraine.